Looking Up: Enjoy the stars with eyes alone or not

Peter BeckerMore Content Now

Friday

Jun 8, 2018 at 1:48 PMJun 8, 2018 at 1:48 PM

This past week we had a very clear, moonless night. It was nice to get back outside and “look up” and take in the stars. There’s no need for a telescope to enjoy them, although the more you look sooner or later you will want to a closer view.Binoculars, which are really two telescopes mounted together, typically magnify your view 7x or 10x, depending on the size you have. Small telescopes set up on a tripod or pedestal offer deeper views, press 30x to 150x. You can go much deeper than that, but there is a limit to how much magnification you can use for a given instrument. It depends on the aperture, the width of the main (objective) mirror in a reflector, and the objective lens in a refracting telescope.You can use about 50x per inch of aperture; a four inch telescope generally all allow you to boost your magnification as high as 200x without the image blurring.This depends, however, on the steadiness of the atmosphere between you and the stars! If you ever have flown in a jet, you may have experienced turbulence and had a bumpy ride. Imagine the starlight, as it is shifted about through miles of wavy air.Stars “twinkle” for the same reason. The effect is easier to see with a bright star close to the horizon. Seen at a low angle, starlight has to pass through a thicker layer of dusty and moist air, which by the way is a further sign the Earth is round! Starlight, as well as the setting and rising Sun and Moon, are also reddened and appear distorted near the horizon.Astronomers refer to the steadiness of the air as “seeing.” On a night of poor seeing, you may have good views of the Moon at low power, but when you boost to high magnification you will see at once that you are seeing the mountains and carters as if they were under a layer of moving water. You won’t discern nearly as much detail.The same goes for splitting close double stars, or for trying to get a good look at a planet such as Mars, Jupiter and Saturn. These three planets can show nice detail on a steady night.This summer, Mars will be at its closest to the Earth since 2003. With a small telescope you may be able to see a few dusky markings and the white polar cap if the air is steady. At present, Mars peeks over the east-southeast horizon at about midnight and is at its highest in the south by dawn.Mars reaches “opposition” from the Sun on July 31, rising around sunset and in the sky all night. Mars will be about as bright as Jupiter, with a deep golden hue.Jupiter is a fine sight on any night; even low power with show the planet as a small, squat disc, with three of four of its largest moons attending it on one side or the other. Higher power can start tho show dark cloud bands and even the “Great Red Spot.” See Jupiter the next clear evening in the southeast; around midnight n really June it will be due south.Saturn shows his wonderful ring system at even 30x to 40x, although the planet and rings will be small. You should be able to see Saturn’s biggest satellite,Titan. Presently, Saturn rises in the southeast in late twilight and is highest looking south at about 2 to 3 a.m.Quality of your optics is also a factor. If you use a reflector, the mirrors also need to be properly aligned with each other to bring what you see into sharp focus. See the instructions that came with the telescope; help is also available online.Again, even if you aren’t in a position to go and buy a telescope, with eyes alone you have a Universe to explore from your backyard. Like mankind did for thousands of years without any optical aid, just look up and take it in. Learn the constellations and a few star names; learn to identify the planets and watch their cosmic travels. Watch for meteors, northern lights and earth satellites. Trace the Milky Way Band on a dark, clear night and realize you are looking at the edge of our galaxy from within. Follow the changing Moon. All this is and more are done with eyes alone, the most wonderful optical instruments of all.New Moon is June 13.Keep looking up!— Peter Becker is Managing Editor at The News Eagle in Hawley, PA. Notes are welcome at news@neagle.com. Please mention in what newspaper or web site you read this column.

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